What Is a Zoo? From Royal Menagerie to Conservation Argument

Collections of exotic animals go back at least to a site in Egypt dated to around 3500 BC containing hippos, elephants and baboons, and they recur wherever a ruler has surplus and reach: the Chinese park described as a garden of intelligence, the menagerie at the Tower of London that held lions from the thirteenth century and an elephant given to Henry III, and the Habsburg collection at Schonbrunn which opened in 1752 and is the oldest zoo still operating. The transition to a public institution came with the Enlightenment and then with empire. London Zoo opened in 1828 as a scientific collection for the Zoological Society and admitted the general public in 1847, and the nineteenth-century zoos that followed were built on the flow of animals arriving from colonies, displayed in barred cages arranged by taxonomy, which made them legible as a catalogue and terrible as habitat. Carl Hagenbeck introduced the barless enclosure with moats in Hamburg in 1907, which is the origin of the modern layout and was invented to please visitors rather than animals.

The argument that zoos are necessary rests on specific claims that can be checked:

• •Species saved from extinction by captive breeding and reintroduction, of which the clear cases include the Arabian oryx, the California condor, the black-footed ferret, Przewalski's horse and the golden lion tamarin
• •Species now extinct in the wild and surviving only in captivity, including several amphibians and the scimitar-horned oryx before its reintroduction
• •Coordinated breeding programmes managing populations across many institutions using studbooks and genetic analysis to avoid inbreeding, which is the main technical activity of accredited zoos
• •Field conservation funding, with the global zoo and aquarium community contributing several hundred million dollars a year to projects in the wild, making it collectively one of the larger conservation funders
• •Research access, since studies of physiology, reproduction, disease and behaviour are far easier in captivity and feed directly into wild conservation
• •Public engagement, on the argument that people protect what they have encountered, which is the weakest-evidenced of the claims

The objections are not only about cage size. Welfare problems in captivity are documented and species-specific: elephants, polar bears, big cats and cetaceans are the groups that consistently fare worst, with reduced lifespans in some studies, high rates of stereotypic behaviour such as pacing and swaying, and, in elephants, foot and joint disease from hard surfaces and insufficient movement. A wide-ranging analysis of carnivores in 2003 found that species with the largest natural home ranges show the most stereotypy and the worst infant mortality, which points at space and ranging behaviour rather than at care. Critics also argue that the conservation claim is used to justify collections dominated by species that are not threatened and are popular, that reintroduction is rare relative to the number of animals held, and that the educational effect is modest, with studies finding limited durable change in knowledge or behaviour from a visit. The deepest objection is ethical rather than empirical, holding that confining a sentient animal for human purposes is wrong regardless of how well it is done.

The better institutions have altered substantially over forty years. Enclosures are designed around the animal's behavioural needs rather than visibility, with complexity, choice, height, substrate and retreat space treated as requirements. Environmental enrichment is a formal discipline, providing problems to solve, food that must be worked for and varying conditions, and its effects on stereotypic behaviour are measurable. Training using positive reinforcement allows animals to participate voluntarily in veterinary procedures, so that a big cat presents a paw for a blood sample rather than being darted. Collections have narrowed, keeping fewer species with more individuals of each, which supports social groups and breeding. Several species have been phased out where welfare cannot be met, with a number of zoos ending elephant keeping and many countries banning cetacean display. Accreditation bodies set standards that carry real consequences, and the gap between an accredited institution and an unregulated roadside attraction is now enormous, which is the distinction that most public argument about zoos fails to make.

Two developments have shifted it. The first is that wild populations have fallen so far that the distinction between captive and wild management is eroding: many remaining populations of large mammals live in fenced reserves, are individually monitored, are moved between sites for genetic reasons and are medically treated, which is a spectrum rather than a boundary. The second is that the technology of conservation is changing, with biobanking of gametes and tissue, assisted reproduction and the possibility of genetic rescue moving some of the function away from live animals. The position most defensible on the evidence is narrow: captive breeding demonstrably saves particular species and has done so repeatedly, zoos fund and enable field work, welfare in accredited institutions has improved and remains poor for a specific group of wide-ranging and highly social species, and the educational and recreational functions that pay the bills are the least evidenced part of the justification.

Zoos began as displays of royal power, became public scientific collections in the nineteenth century stocked through empire, and moved to barless enclosures from 1907 for the benefit of visitors. The conservation case rests on real successes including the Arabian oryx and the California condor, on coordinated breeding programmes using studbooks, and on several hundred million dollars a year of field funding. Welfare remains worst for wide-ranging species including elephants, big cats and cetaceans, and the gap between accredited zoos and unregulated attractions is the distinction the public argument usually misses.